Method and Apparatus for Transmitting Information About a Channel in a Wireless Communication System

1. A method for feeding back channel information, the method comprising: receiving, by a user equipment (UE) configured with one or more cells, information on a maximum number of ranks; transmitting, by the UE, first channel information generated based on rank information; and transmitting, by the UE, second channel information which is generated based on the same rank information as the rank information used for generating the first channel information, wherein the maximum number of ranks is used to determine the rank information.

2. The method of claim 1 , further comprising: receiving rank-related information determined by a base station based on the rank information.

3. The method of claim 1 , wherein the second channel information includes at least one of a precoding matrix indicator (PMI) and channel quality information (CQI).

4. The method of claim 1 , further comprising: determining the rank information corresponding a number of antenna layers.

5. The method of claim 1 , wherein: the transmission of the first channel information is associated with a first feedback process, and the transmission of the second channel information is associated with a second feedback process.

6. The method of claim 5 , wherein: the first feedback process is related to a first reference signal, and the second feedback process is related to a second reference signal.

7. The method of claim 6 , wherein each of the first and second reference signals correspond to at least one of a cell-specific reference signal (CRS) and a channel state information reference signal (CSI-RS).

8. The method of claim 1 , wherein each of the first and second channel information is channel state information (CSI).

9. The method of claim 1 , wherein the first channel information or the second channel information is transmitted on a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH).

10. The method of claim 1 , wherein rank-related information is received through downlink control information (DCI) scrambled with a radio network temporary identity (RNTI).

11. A user equipment (UE), comprising: a Radio Frequency (RF) unit configured to transmit and receive a radio signal; and a processor coupled to the RF unit and configured with one or more cells thereby performing: receiving information on a maximum number of ranks; transmitting first channel information generated based on rank information; and transmitting second channel information which is generated based on the same rank information as the rank information used for generating the first channel information, wherein the maximum number of ranks is used to determine the rank information.

12. The UE of claim 11 , wherein the processor further performs: receiving rank-related information determined by a base station based on the rank information.

13. The UE of claim 11 , wherein the second channel information includes at least one of a precoding matrix indicator (PMI) and channel quality information (CQI).

14. The UE of claim 11 , wherein the processor further performs: determining the rank information corresponding a number of antenna layers.

15. The UE of claim 11 , wherein: the transmission of the first channel information is associated with a first feedback process, and the transmission of the second channel information is associated with a second feedback process.

16. The UE of claim 15 , wherein: the first feedback process is related to a first reference signal, and the second feedback process is related to a second reference signal.

17. The UE of claim 16 , wherein each of the first and second reference signals correspond to at least one of a cell-specific reference signal (CRS) and a channel state information reference signal (CSI-RS).

18. The UE of claim 11 , wherein each of the first and second channel information is channel state information (CSI).

19. The UE of claim 11 , wherein the first channel information or the second channel information is transmitted on a Physical Uplink Control Channel (PUCCH) or a Physical Uplink Shared Channel (PUSCH).

20. The UE of claim 11 , wherein rank-related information is received through downlink control information (DCI) scrambled with a radio network temporary identity (RNTI).